Brush seal

ABSTRACT

A brush seal and brush seal segment for use in a rotary device are provided. In one embodiment, the invention provides a brush seal comprising: a plurality of brush seal segments, each segment including: an arcuate fence; an arcuate backplate substantially circumferentially coextensive with the arcuate fence, the arcuate backplate including a first end and a second end; and a plurality of brush seal bristles between the arcuate backplate and the arcuate fence, the plurality of brush seal bristles being angled with respect to a radial axis of the arcuate backplate and at least one of the first end and the second end of the arcuate backplate; and a static member to which at least one of the plurality of brush seal segments is affixed.

BACKGROUND OF THE INVENTION

Embodiments of the invention relate generally to brush seals and, moreparticularly, to segmented brush seals having a plurality of brushbristles angled with respect to an end of a backplate. Such anarrangement improves pressure balance and backplate support for thebrush bristles, thereby preventing or reducing damage to brush bristlesadjacent ends of the brush seal segments. Such an arrangement alsoreduces leakage through segment gaps to improve performance of the brushseal.

Known segmented brush seals may include segments havingradially-oriented or angled brush bristles. The backplates of suchsegments typically have ends parallel to the brush bristles. Gaps willgenerally exist where segment ends meet to avoid arch-binding thesegments in operation, resulting in increased brush seal radialclearance. As a consequence, there will be direct leakage paths throughthe gaps between brush seal segments, resulting in more leakage and adecrease in seal efficiency. In addition, brush bristles adjacent asegment end may fall into the gap and get damaged from lack of supportand less pressure balancing and/or from rotor excursion, which bothincreases leakage and causes instability of nearby brush bristles,further decreasing the efficiency of the brush seal and inducingextensive bristle damage.

BRIEF DESCRIPTION OF THE INVENTION

A brush seal and brush seal segment for use in a rotary device areprovided.

In one embodiment, the invention provides a brush seal comprising: aplurality of brush seal segments, each segment including: an arcuatefence; an arcuate backplate substantially circumferentially coextensivewith the arcuate fence, the arcuate backplate including a first end anda second end; and a plurality of brush seal bristles between the arcuatebackplate and the arcuate fence, the plurality of brush seal bristlesbeing angled with respect to a radial axis of the arcuate backplate andat least one of the first end and the second end of the arcuatebackplate; and a static member to which at least one of the plurality ofbrush seal segments is affixed.

In another embodiment, the invention provides a brush seal segmentcomprising: an arcuate fence; an arcuate backplate substantiallycircumferentially coextensive with the arcuate fence, the arcuatebackplate including a first end and a second end; and a plurality ofbrush seal bristles between the arcuate backplate and the arcuate fence,the plurality of brush seal bristles being angled with respect to aradial axis of the arcuate backplate and at least one of the first endand the second end of the arcuate backplate.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this invention will be more readilyunderstood from the following detailed description of the variousaspects of the invention taken in conjunction with the accompanyingdrawings that depict various embodiments of the invention, in which:

FIG. 1 shows a cross-sectional view of a rotary device having a brushseal and a rotor.

FIG. 2 shows portions of a brush seal segment according to an embodimentof the invention.

FIG. 3 shows a brush seal segment according to an embodiment of theinvention.

FIG. 4 shows a portion of a brush seal according to an embodiment of theinvention.

FIG. 5 shows a portion of a brush seal according to another embodimentof the invention.

FIG. 6 shows a portion of a brush seal according to yet anotherembodiment of the invention.

FIG. 7 shows a brush seal segment according to still another embodimentof the invention.

It is noted that the drawings of the invention are not to scale. Thedrawings are intended to depict only typical aspects of the invention,and therefore should not be considered as limiting the scope of theinvention. In the drawings, like numbering represents like elementsamong the drawings.

DETAILED DESCRIPTION OF THE INVENTION

Turning now to the drawings, FIG. 1 shows a cross-sectional view of arotary device 100 (e.g., gas turbine, steam turbine, generator, etc.)comprising a rotor 10 surrounded by a substantially circular staticmember 20 and a brush seal 90 therebetween. Brush seal 90 includes aplurality of segments 30A, 30B, 30C, 30D, 30E, 30F, one or more of whichmay be affixed to static member 20. Such a brush seal may include anynumber of segments, typically between two and 12 segments. For the sakeof brevity, the segments will be described further with respect only tosegment 30A.

Each segment 30A includes an arcuate fence 40A, an arcuate backplate(shown in subsequent figures and described further below), and aplurality of brush bristles 70A. The plurality of brush bristles 70A aredisposed between fence 40A and the backplate, and extend beyond an innerarcuate edge 46A of fence 40A, such that brush bristles 70A may sealagainst rotor 10 as it rotates along path A.

As can be seen in FIG. 1, brush bristles 70A are angled at an angle αrelative to a radial axis R of rotor 10, segment 30A, and static member20. Similarly, a first end 42A and second end 44A of fence 40A areangled at an angle β and an angle γ, respectively, with respect toradial axis R. Although not essential, angles β and γ are typically thesame, but they can be different from the bristles angle α. Such anglesgenerally range, for example, from about 1° to about 60° with respect toradial axis R. As one skilled in the art will recognize, of course, inorder for adjacent segments of brush seal 90 to properly align andprovide a functional seal, a first end (e.g., 42A) of a first fence(e.g., 40A) must have an angle substantially the same as an angle of asecond end (e.g., 44F) of an adjacent second fence (e.g., 40F).

FIG. 2 shows a fence 40A, brush bristles 70A, and arcuate backplate 50Aaccording to one embodiment of the invention. Arcuate backplate 50A isshown circumferentially coextensive with fence 40A. Brush bristles 70A,first end 42A, and second end 44A are angled, α, β, and γ, respectively,relative to radial axes R₁ and R₂. A first end 72A and second end 74A ofbristles 70A are angled substantially at the same angle α. As shown inFIG. 2, angles β and γ are substantially the same. Backplate 50Aincludes a first end 52A and second end 54A, each of which issubstantially parallel to a radial axis R₁, R₂, respectively.

FIG. 3 shows backplate 50A in place behind fence 40A and brush bristles70A to form segment 30A. As can be seen in FIG. 2, a portion 51A ofbackplate 50A extends beyond second end 74A of the bristle pack. Portion51A serves to support a portion of the brush bristles of an adjacentsegment. Such an arrangement is shown in FIG. 4, where an extendingportion 71B of brush bristles 70B is disposed in front of portion 51A ofbackplate 50A when segments 30A and 30B are in place. This stepped gapdesign is made possible by the angled ends 72A, 74A of bristles 70Acombined with substantially radial ends 52A, 54A of backplate 50A.

Other embodiments incorporating a stepped gap design are possible, ofcourse. For example, FIG. 5 shows an embodiment of the invention whereinportion 151A of backplate 150A extends beyond first end 142A of arcuatefence 140A, rather than beyond second end 144A, as would be the case inthe embodiment shown in FIGS. 2-4.

In another embodiment of the invention, such as that shown in FIG. 6,first end 252A, second end 254A, or both, of backplate 250A may beangled δ relative to radial axes R₁, R₂, respectively. Typically, angleδ would be to a side of a radial axis opposite that of angle α. That is,angle α will typically be “positive” (as defined in the direction ofrotor rotation) and angle δ “negative,” (as against the rotor rotationaldirection), such that the “negative” angle δ increases portion 251A ofbackplate 250A extending beyond first end 272A of bristles 270A. As usedherein, “positive” and “negative” are meant merely to illustrateopposite sides of a radial axis rather than any value of an anglerelative to such an axis. Angle δ may have a value similar to that ofangle α, i.e., between about 1° and about 60°, while β and γ may be thesame as either bristle angle α or backplate end angle δ. Formanufacturing reasons, the fence may have the same angle as the bristlesand be aligned with the bristle pack along the segment ends.

FIG. 7 shows a brush seal segment 330A according to another embodimentof the invention, wherein first end 342A and second end 344A of fence340A are substantially parallel to radial axes R₁ and R₂, respectively,as are the ends of the backplate (not shown). That is, only brushbristles 370A are angled α with respect to radial axes R₁ and R₂. Suchan arrangement forms a pair of voids 362A, 364A between fence 340A andthe backplate, into which brush bristles from an adjacent segment may beinserted during assembly of the brush seal.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any related or incorporated methods. Thepatentable scope of the invention is defined by the claims, and mayinclude other examples that occur to those skilled in the art. Suchother examples are intended to be within the scope of the claims if theyhave structural elements that do not differ from the literal language ofthe claims, or if they include equivalent structural elements withinsubstantial differences from the literal language of the claims.

1. A brush seal comprising: a plurality of brush seal segments, each segment including: an arcuate fence; an arcuate backplate substantially circumferentially coextensive with the arcuate fence, the arcuate backplate including a first end and a second end; and a plurality of brush seal bristles between the arcuate backplate and the arcuate fence, the plurality of brush seal bristles being angled with respect to a radial axis of the arcuate backplate and at least one of the first end and the second end of the arcuate backplate; and a static member to which at least one of the plurality of brush seal segments is affixed.
 2. The brush seal of claim 1, wherein at least one of the first end and the second end of the arcuate backplate is substantially parallel to a radial axis of the arcuate backplate.
 3. The brush seal of claim 2, wherein both the first end and the second end of the arcuate backplate are substantially parallel to radial axes of the arcuate backplate.
 4. The brush seal of claim 1, wherein the plurality of brush seal bristles is positively angled with respect to the radial axis of the arcuate backplate.
 5. The brush seal of claim 4, wherein at least one of a first end and a second end of the arcuate fence is substantially parallel to the brush seal bristles.
 6. The brush seal of claim 4, wherein at least one of the first end and the second end of the arcuate backplate is negatively angled with respect to the radial axis of the arcuate backplate.
 7. The brush seal of claim 6, wherein at least one of the first end and the second end of the arcuate backplate is negatively angled between about 1° and about 60° with respect to the radial axis of the arcuate backplate.
 8. The brush seal of claim 1, wherein the plurality of brush seal bristles is positively angled between about 1° and about 60° with respect to the radial axis of the arcuate backplate.
 9. The brush seal of claim 8, wherein at least one of the first end and the second end of the arcuate backplate is negatively angled between about 1° and about 60° with respect to the radial axis of the arcuate backplate.
 10. The brush seal of claim 1, wherein at least one of a first end and a second end of the arcuate fence is substantially parallel to the radial axis.
 11. A brush seal segment comprising: an arcuate fence; an arcuate backplate substantially circumferentially coextensive with the arcuate fence, the arcuate backplate including a first end and a second end; and a plurality of brush seal bristles between the arcuate backplate and the arcuate fence, the plurality of brush seal bristles being angled with respect to a radial axis of the arcuate backplate and at least one of the first end and the second end of the arcuate backplate.
 12. The brush seal segment of claim 11, wherein at least one of the first end and the second end of the arcuate backplate is substantially parallel to a radial axis of the arcuate backplate.
 13. The brush seal segment of claim 12, wherein both the first end and the second end of the arcuate backplate are substantially parallel to radial axes of the arcuate backplate.
 14. The brush seal segment of claim 11, wherein the plurality of brush seal bristles is positively angled with respect to the radial axis of the arcuate backplate.
 15. The brush seal segment of claim 14, wherein at least one of a first end and a second end of the arcuate fence is substantially parallel to the brush seal bristles.
 16. The brush seal segment of claim 14, wherein at least one of the first end and the second end of the arcuate backplate is negatively angled with respect to the radial axis of the arcuate backplate.
 17. The brush seal segment of claim 16, wherein at least one of the first end and the second end of the arcuate backplate is negatively angled between about 1° and about 60° with respect to the radial axis of the arcuate backplate.
 18. The brush seal segment of claim 11, wherein the plurality of brush seal bristles is positively angled between about 1° and about 60° with respect to the radial axis of the arcuate backplate.
 19. The brush seal segment of claim 18, wherein at least one of the first end and the second end of the arcuate backplate is negatively angled between about 1° and about 60° with respect to the radial axis of the arcuate backplate.
 20. The brush seal segment of claim 11, wherein at least one of a first end and a second end of the arcuate fence is substantially parallel to the radial axis. 